Modular jacks for connecting telecommunications equipment are used for two broad categories of signal transmission: analog (voice) and digital (data) transmission. While these categories overlap somewhat since digital systems may be used for voice transmission, there is a significant difference in the data rates transmitted by each type of system. A low speed system ordinarily transmits at data rates from about 10 to 16 megabits per second (Mbps), while a high speed system transmits at data rates of 155 Mbps or higher. Often, high speed installations are based on asynchronous transfer mode transmission and utilize shielded and unshielded twisted pair cables.
With recent increases in the speed of data transmission, requirements for reduction or elimination of crosstalk have become important for electrical connectors. Crosstalk is a phenomena that occurs when a part of the electromagnetic energy transmitted through one of multiple conductors in a connector causes electrical currents in the other conductors. Another problem is common mode electromagnetic interference or noise. Such common mode interference is often most severe in conductors having the same length, and occurs when a parasitic signal induced by electrostatic discharge (ESD), lightning or simultaneous switching of semiconductor gates arrives in an adjacent electrical node through multiple conductors at the same time.
Another requirement driving telecommunication connector design is that the telecommunications industry has reached a high degree of standardization in modular jack design. Outlines and contact areas are essentially fixed and must be interchangeable with other designs. It is, therefore, important that any novel modular jack substantially allow the use of conventional parts or tooling in its production.
A solution to the above-noted problems is proposed in U.S. Pat. No. 5,599,209, to Belopolsky, the inventor herein, entitled, "Method of Reducing Electrical Crosstalk and Common Mode Electromagnetic Interference and Modular Jack for Use Therein" ("Belopolsky '209"). This solution was proposed to reduce crosstalk and common mode electromagnetic interference in a modular jack by: (a) separating round wire conductors into two groups that are positioned in a distinct, separate area in the modular jack; (b) increasing the distance between adjacent conductors; (c) reducing the common length between adjacent conductors; and (d) using significantly different lengths for adjacent conductors. In the Belopolsky '209 connector, a first plurality of round wires extends in a common vertical plane from the bottom wall of the jack housing across the open rear end to the top wall and then extend horizontally forward and then angularly downwardly and rearwardly back toward the rear open end. A second plurality of wires extends first in a common vertical plane from the bottom wall across only a part of the rear open end and then extends obliquely, horizontally and upwardly toward the open front end. The downwardly extending oblique plane of the first plurality of wires and upwardly extending oblique plane of the second plurality of wires have a common length between 0.8 inch to 1.0 inch, while the length of the horizontal section of the first group of wires is relatively much longer being preferably 0.6 inch to 2.0 inch.
While the Belopolsky '209 modular jack is a vast improvement over the prior art modular jack connectors, there is still a need for a modular jack which further reduces crosstalk in telecommunications equipment. There is also a need for a modular jack which will further reduce common mode electromagnetic interference in telecommunications equipment. Particularly, there is a need for a modular jack connector that meets or exceeds Category 5 requirements. There is also a need for such an improved modular jack to be interchangeable with prior art modular jacks and to be manufactured using conventional parts and tooling. The present invention provides such a solution.